Seal ring structure of semiconductor device is mainly used to protect the chip of the semiconductor device from being damaged during dicing process. Specifically, seal ring structure may prevent damages to the chip due to cracks generated by dicing blades.
Usually, the seal ring structure is a metal shielding ring formed by overlapped contact holes, through vias, and metal layers. The seal ring structure may be formed at a position with a certain distance away from the chip, and may also keep a certain distance away from the dicing path. For different devices, the distance between the seal ring structure and the chip, and the distance between the seal ring structure and the dicing path may be different.
In addition to providing protection for the chip during dicing process, seal ring structure may also play other roles. For example, the seal ring structure may shield noise signals coming from outside of the chip; and the seal ring structure may also prevent moisture from entering the chip through fracture surfaces on the edges.
However, seal ring structures fabricated by existing methods may cause degradation of electrical performance of semiconductor devices. The disclosed fabrication method and semiconductor structure are directed to solve one or more problems set forth above and other problems in the art.